Electrical control apparatus



Feb. 16, 1965 c. w. GILBERT 3,170,093

ELECTRICAL CONTROL APPARATUS Filed July ze. 1962 RFI ce1 j c@ 1 Raza' m14 .s'W B5 FM T(ZL REI RF.; 5H

United States Patent 3,170,093 ELECTRICAL CONTROL APPARATUS Chalmers W. Gilbert, Penn Hills Township, Allegheny County, Pa., assignor to Westinghouse Air Brake Company, Wilmerding, Pa., a corporation of Pennsylvania Filed July 26, 1962, Ser. No. 212,507 14 Claims. (Cl. 317-135) My invention pertains to electrical control apparatus, and particularly to apparatus responsive only to a predetermined sequence of actuation of first and second circuit controllers. More specifically my invention pertains to apparatus for actuating a relay or other device in response only to a predetermined sequence of closure of first and second sets of contacts regardless of whether said sequential closure of the contacts occurs in an overlapping or non-overlapping manner.

There are many electrical control systems in which it is desired that a relay or other electrically controlled device will be actuated only in response to a preselected sequence of actuation of first and second circuit controllers. For example, in a system for recording the number of road vehicles passing in a predetermined direction only through a double direction vehicle trafiic section of roadway having sufficient clearance for the width of only a single vehicle at a time, it is oftentimes the practice to provide a wheel actuated switch or treadle in such section of roadway so that the treadle will be depressed by the wheels of each vehicle passing through the roadway section. record only the vehicle passing in said predetermined direction through the section of roadway, it is necessary to determine the direction of passage of each vehicle before the recording system is or is not actuated as the case may be. A single treadle-actuated set of contacts or circuit controller is not usually employed in such a vehicle recording system because such `a single set of contacts or circuit controller cannot be made directionally responsive without a relatively complex mechanical latching arrangement to prevent the set of contacts from being actuated when a wheel of a vehicle passes over the treadle in the non-recording direction. Accordingly, it is the usual practice to provide two successive treadles each having a single set of contacts, or a single treadle having two sets of C011- tacts so arranged as to be actuated in a sequence according to the direction of passage of a vehicle wheel over the single treadle. In conjunction with such contacts or circuit controllers it has heretofore been the practice to employ a group of relays which are selectively responsive to the direction of passage of the vehicles, that is, to the sequence of actuation of said sets of contacts or circuit controllers. Contacts of the relays are employed to control the operation or to prevent the operation of the recording system as the case may be. For obvious economic reasons it would be desirable to employ less costly devices than relays for determining the direction of passage of the vehicles past the vehicle recording point.

It is, therefore, an object of my invention to provide improved electrical control apparatus responsive only to a predetermined sequence of actuation of first and second circuit controllers and employing a minimum of relays.

It is a second object of my invention to provide apparatus such as that set forth above and which operates in the desired manner regardless of whether the sequential actuation of the circuit controllers is an overlapping or non-overlapping type of actuation.

Another object of my invention is to provide apparatus such as that described above and which will operate in the desired manner in response to a relatively briefer period of closure of the circuit controller contacts than the apparatus heretofore employed.

In accomplishing the above objects of my invention I In order that the vehicle recording system will employ a pair of energy storing devices or capacitors in conjunction with the sequentially actuated circuit controllers, and provide a circuit arrangement whereby energy is stored in one of said capacitors upon the actuation of a first of said circuit controllers and is thereafter discharged -to operate a relay or other electrically responsive device upon the actuation of the second circuit controller. In modifications of such apparatus I employ an electronic switching device, such as a transistor, to provide greater sensitivity for operation of said relay or other electrically responsive device.

Other objects and characteristic features of my invention will become apparent as the description proceeds.

I will describe four forms of apparatus embodying my invention and will then point out the novel features therey of in claims.

In the accompanying drawings:

FIG. 1 is a diagrammatic view showing one form of apparatus embodying my invention and employing a polar biased relay which is energized in response to a predetermined sequence of actuation of first and second circuit controllers.

FIG. 2 is a diagrammatic view -of an alternate form of the `apparatus of FIG. 1 in which the polar biased relay of FIG. 1 is replaced by a conventional neutral relay having a diode connected in multiple with the relay winding.

FIG. 3 is a diagrammatic View of a third form of apparatus embodying my invention and employing an electronic switching device or transistor to control the energization of a neutral relay such as employed in FIG. 2.

FIG. 4 s a diagrammatic view of an alternate form of the apparatus of FIG. 3 employing the electronic switching device or transistor shown in FIG. 3, and an additional diode and control circuitry.

Similar reference characters refer to similar parts in each of the views.

Referring first to FIG. l, there is shown at the left hand side thereof, a switch designated SW and comprising first and second sets of contacts or circuit control- 1ers designated CCI and CC2, respectively. Circuit controller CCI includes a resilient leaf or contact plate P1 which when actuated in a downward direction as viewed 0n the drawing, makes physical contact with a contact plate P2 so that an electrical circuit may be completed between plates P1 and P2. Similarly, circuit controller CC2 includes a resilient leaf or contact plate P3 which when actuated in a downward direction makes physical contact with plate P2 so that an electrical circuit may be completed between plates P3 and P2.

As previously discussed, switch SW may be considered to be a treadle actuated switch arranged to be depressed by the wheels of a vehicle passing thereover so that circuit controllers CCI and CC2 are actuated to contact closing conditions in a sequence according to the direction of passage of the vehicle wheels. Such treadle actuated switches are well known and it is to be understood that the details of switch SW form no part of my 1nvention, but that the invention is intended to operate in response to a predetermined sequence of operation to contact closing conditions of any type of first and second circuit controllers. For example, circuit controllers CC1 and CC2 could each be a spring return push button which must be manually actuated in a predetermined sequence for the proper response of the apparatus of my invention, or any other type of circuit controllers intended to be actuated in a sequential manner could be employed. As heretofore pointed out and as pointed out in more detail hereinafter, it is immaterial to the operation of my invention whether controllers CCI and CC2 are sequentially actuated to circuit closing conditions in an overlapping or non-overlapping manner.

Referring further to FIG. l, there is shown, in the conventional manner, first and second energy storing devices or capacitors CAPI and CAPZ, first and second resistors REI and REZ, and a battery BT having its positive and negative terminals designated by the conventional symbols -tand respectively.

A polar biased relay designated by the reference character R is shown in the drawing by a rectangle representing the winding of the relay'. The arrow enclosed in the rectangle representing such winding indicates the direction of the biasing of the relay, that is, the direction in which positive current must rlow through the relay winding to cause the contacts of the relay to become picked up. current through the winding of the relay must be from left to right, as viewed on the drawing, to cause pickup of the relay contacts. Such biased relays are well known in the electrical art. A normally open Contact a is shown below the rectangle representing the relay winding and is indicated as controlled thereby by the dotted line extending from such rectangle to the movable part of the contact. It will, therefore, be readily understood that Contact a is actuated to a circuit closing position only when current flows through the winding of the relay in the direction from left to right. The specific circuits controlled by contact a ot relay R (as well as the circuits controlled by contacts a of relays RI of FIGS. 2, 3 and 4) are not shown in the drawing since they form no part of my invention, but it is to be Vunderstood that such contact may be employed to control any desired type of indication or control circuits, or an electrically actuated counter or other such device.

The positive terminal (-i-) of battery BT is connected in multiple to the right hand side of the winding ot relay R and a first end of resistor REZ. The left hand side of the winding of relay R is connected in multiple to one side of capacitor CAPIand a first end of resistor REI. The second end of resistor REZ is connected in multiple to a first side of capacitor CAPZ and to` contact plate P3 of circuit controller CCZ. The second sides of capacitors CAPI and CAPZ and the second end of resistor REI are connected in multiple with each other and to contact plate P2 which is common to both controllers CCI and CCZ. Contact plate P of controller CCI is connected to the negative terminal of battery BT.

It should be pointed out at this time that resistor REI is employed for discharging or bleeding capacitor CAPI, under conditions hereinafter described, and has a high resistance so that it normally draws little current. lt should also be pointed out that capacitors CAPI and CAPZ, resistor REZ, and the resistance of the winding of relay R are proportioned so that if circuit controller CCI only is actuated to its circuit closing position at any time, capacitor CAPZ will be charged, over the circuits to be hereina'iter discussed, to at least as high a voltage as capacitor CAPI. For reasons which will be made apparent in the following discussion, the charging of capacitor CAPZ under such conditions will, when controller CCI thereafter returns to its unactuated position, prevent the improper energization of relay R.

The apparatus of FIG. l operates in the following described manner.

(I)` Actuation of circuit controller CCI followed by actuation of circuit controller CCZ (termed normal sequence of operation):

When controller CCI is actuated, current will flow over a circuit which may be traced from the positive terminal of battery BT, winding 'of relay R, right hand side of capacitor CAPI, left hand side of CAPI, contact plate PZ, contact plate PI, and thence to the negative terminal of battery BT. At the same time current also flows from the positive terminal of battery BT, through resistor REZ, capacitor CAPZ, and

It is thus apparent that the flow of thence to contact plate P2, contact plate PI and over the remainder of the circuit traced above. Capacitors CAPI and CAPZ become charged by such iiow of current but relay R remains released since the current flow through the winding or the relay is in the direction from right to left.

lt circuit controller CCZ is actuatedv before controller CCI returns to its unactuated position, the following operation of the apparatus occurs. Y

The actuation of' CCZ immediately discharges capacitor CAPZ over an obvious circuit including contact plates PZ and P3 of switch SW. At the same time the positive terminal of battery BT is connected to the negative terminal of the battery through resistor REZ and over contact plates P3, PZ and P1 of switch SW, but such closed circuit produces no action and resistor REZ prevents a direct short circuit of the battery at such time. When controller CCI thereafter returns to its unactuated position and opens the circuit through contact plates P1 and P2, capacitor CAPI will start to discharge through the winding of relay R in the direction from lett to right, and

through resistor REZ and contact plates P3 and P2. If controller'CCZ returns to its unactuated position before capacitor CAPI is discharged, the charge on capacitor CAPI will continue to ow through the winding of the relay R in the same direction and will charge capacitor CAPZ until the two capacitors have an equal charge. Relay R thus'becomes picked up by the current flowing through the relay winding in the direction from left to right, even though the actuation of controller CCZ to its contact closing position is of extremely short duration.

If circuit controller CCZ is actuated after controller CCI returns to its unactuated position, the following operation of the apparatus takes place.

The actuation of CCZ to its contact closing position immediately dischargesV capacitor CAPZ and also starts the discharge of capacitor CAPI through relay R in the direction from left to right over the previously mentioned circuit including resistor REZ and contact plates P2 and P3 of switch SW. As discussed above, if circuit controller CCZ returns to its unactuated position before capacitor CAPI is discharged, the charge on capacitor CAPI will continue to flow through relay R in the same direction until the charge on capacitor CAPZ equals that on capacitor CAPI. Relay R thus becomes picked up in response to the energy flowing through the relay winding in the direction from left to right.

(Z) Actuation of circuit controller CCZ followed by actuation of circuit controller CCI (termed reverse sequence of operation):

When controller CCZ is actuated, no resultant operation of the apparatus occurs since there is no charge on capacitors CAPI and CAPZ. When controller CCI is thereafter actuated, capacitor CAPI is charged, as previously described, with the direction of current from right to left through the winding of relay R, When controller CCZ returns to its unactuated position, capacitor CAPZ becomes charged thus making the charges on the two capacitors equal. When controller CCI thereafter re' turns to its unactuated position, capacitor CAPI discharges relaitvely slowly through resistor REI. At the same time capacitor CAPZ discharges relatively slowly through resistor REZ, the winding of relay R, and resistor REI. The direction of current through the winding of relay R is, at such time, from right to left and the relay remains released. It is, therefore, readily apparent that for sequential circuit controller operation CCZ-CCI all the current through the winding of relay R is in the direction from right toy left and the relay remains released.

As previously mentioned, if controller CCI lonly is actuated at any time, capacitors CAPI and CAPZ will become equally charged so that, upon the opening of contact plates PI and P2, no current will ow from capaci- Ycome picked up.

arranca tor CAPI through the winding of relay R in a direction to cause pickup of the relay. The energy stored in capacitors CAPI and CAPZ under these conditions will, after the opening of P1 and P2, discharge through resistor REI as described above.

It is obvious that if controller CCZ only is actuated at any time no operation of the apparatus takes place since no circuit is completed to battery BT at such time.

By the foregoing discussion it will be readily understood that relay R is actuated, that is, becomes picked up when and only when circuit controllers CC1 and CCZ of switch SW are sequentially actuated, in that order, to their circuit closing positions.

Referring to FIG. 2 of the drawings, the apparatus is identical to that of FIG. l except that relay R of FIG. l is replaced by a neutral (unbiased) relay RI having an asymmetric unit or diode D connected across the winding of the relay so that, when controller CCI is actuated, the posit-ive energy from battery BT can flow through diode D, in the low resistance direction thereof, to charge capacitor CAPI. Thus, relay R1 will remain released at such time. However, when capacitor CAPI is discharging, as previously discussed in connection with FIG. l, the energy from capacitor CAPI will flow through the winding of relay RI, due to the high resistance of diode D to such direction of current ilow, and relay R1 will be- It is, therefore, readily apparent that the apparatus of FIG. 2 and the operation of such apparatus is, with the exceptions set forth identical to that of FIG. l, and no further discussion of the details of such apparatus and its operation are believed necessary.

Referring now to FIG. 3, the apparatus arrangement is similar to that of FIG. 2 with the following exceptions. In place of diode D and the winding of relay R1, two series connected resistors RES and RE4 are connected between the positive terminal of battery BT and the first side of capacitor CAPI. An electronic switching device here shown as a PNP type transistor T is provided and has its base BS connected to the positive terminal of battery BT and its emitter EM connected to the series connection between resistors RES and RE4. The collector CL of transistor T is connected to a first side of the winding of relay RI, which is similar to relay RI of FIG. 2. A second battery designated BTI is provided and the negative terminal of battery BT1 is connected to the second side of the winding of relay R1. The positive terminal (-I) of battery BT1 is connected to emitter EM of transistor T. An asymmetric unit or diode DI is connected across the winding of relay RI with the low resistance direction of the diode being ina direction from said second side of relay RI to said first side of the relay. Diode DI is provided in the modication of FIG. 3 (as well as in the modification of FIG. 4 discussed below) only to protect transistor T from the energy induced in the winding of relay RI when the relay becomes deenergized. ySuch arrangement is well known and it is readily apparent that diode DI dissipates the energy induced across the winding of relay R1, without such energy flowing through the emitter to collector circuit of transistor T.

The apparatus of FIG. 3 operates similarly to that of FIGS. 1 and 2 for the different sequences of actuation of circuit controllers CCI and CCZ, except as set forth below.

Under normal conditions as shown in FIG. 3, that is, with both controllers CC1 and CCZ unactuated, transistor T is nonconducting, as is obvious. Relay R1 is, therefore, normally released since no current is owing in the emitter to collector circuit of transistor T at such time. Similarly, when capacitor CAPI is being charged from battery BT, under the conditions of actuation of control- 1ers CC1 and CCZ previously discussed in connection with FIGS. l and 2, transistor T is nonconducting since the base BS of transistor T is, due to the voltage drop across resistor RE4 at such time, at a more positive polcapacitor CAPI is discharging through controller CCZ or into capacitor CAP2, the discharge path is through resistor RES and over parallel paths comprising resistor RE4 and the emitter-base junction of transistor T, then through resistor REZ. At such time the emitter EM of transistor T becomes more positive than the base BS of the transistor and current from the positive terminal of battery BTI flows through the emitter to collector circuit and the winding of relay R1 to the negative terminal of battery BT1. This causes relay RI to become picked up and front contact a of the relay closes. It is thus apparent that the apparatus of FIG. 3 operates in a manner similar to that of FIGS. l and 2. The inclusion of the electronic switch or transistor T provides greater sensitivity of operation of the apparatus, and the energy handled by the capacitors may be much smaller thus permitting the use of smaller components.

The apparatus of FIG. 4 is similar to that of FIG. 3 except that resistor RE4 of FIG. 3 is replaced by a diode D2, and emitter EM of transistor T is connected through a resistor RES to the negative terminal of battery BT. By this arrangement, in the normal condition of the apparatus as shown in FIG. 4, that is, with neither controller CC1 or CCZ actuated, transistor T is in the reverse-biased or cut-off condition due to the voltage drop across diode D2 in the circuit extending from the positive terminal of battery BT, through diode D2 in its low resistance direction, and through resistor RES to the negative terminal of battery BT. When capacitor CAPI is discharging either through controller CCZ in its actuated position, or into capacitor CAP2, the major portion of the current flows through resistor RE3, then ilows through the emitter-base junction of transistor T and through resistor REZ. Only a negligible amount of such current will iiow through the two paths in parallel with the emitter-base junction, that is (l) through diode D2 in its high resistance direction and (2) through resistor RES (which is selected to be relatively high resistance) and battery BT. Since the major portion of capacitor CAPI discharge current flows through the emitter-base junction of transistor T, the transistor is held in the conducting condition through its emitter to collector circuit at lower levels of current from capacitor CAP 1 than in the arrangement of FIG. 3. Relay RI becomes picked up at such time over the circuit extending from the positive terminal of battery BTI, emitter to collector circuit of transistor T, and through the winding of the relay to the negative terminal of battery BTI. It is thus apparent that the apparatus of FIG. 4 operates in a manner similar to that of FIG. 3 but that diode D2 forces the major part of capacitor CAPI discharge current through the emitter-base junction of transistor T and, since transistor ,T is held in the conducting condition (emitter to collector) at lower levels of current from capacitor CAPI than in the arrangement of FIG. 3, it is capable of operation with less energy stored in capacitor CAPI. Thus, the system of FIG. 4 will operate for shorter periods of closure of controller CCI than will the system of FIG. 3.

Apparatus such as herein disclosed is relatively simple and reliable and provides more positive operation, under conditions of relatively short closures in a preselected sequence of the contacts of first and second circuit controllers, than the relay systems heretofore employed for such purpose.

Although I have herein shown and described only four forms of apparatus embodying my invention, it will be understood that various changes and modifications may be made therein within the scope of the appended claims arranca t without departing from the spirit and scope of my invention.

Having thus describe/d my invention, What I claim is:

1. Means for detecting a predetermined sequence of actuation to circuit closing positions of first and second normally open circuit controllers, said means,lcompris ing, in combination:

(a) a capacitor,

(b) a source of direct current energy,

(c) electrical contact controlling means actuated only when direct current energy is supplied thereto in a predetermined direction,

(d) first circuit means responsive to an actuation of said first circuit controller prior to an actuation of said second circuit controller for supplying direct current energy from said source to said contact controlling means in a direction opposite to said predetermined direction and a-t the Sametime to said capacitor for charging thereof, and

(e) second circuit means responsive thereafter to an actuation of said second circuit controller for discharging said capacitor through said contact controlling means in said predetermined direction.

2. in combination:

(c) first -and second normally open circuit controllers each actuable to a circuit closing position,

(b) a source of direct current energy,

(c) contact actuating means having first and second terminals and a contact actu-able to a closed position only when said first and second terminals are connected to the positive and negative terminals of a source of direct current energy,

(d) first and second electrical energy storing devices,

(e) first circuit means connecting the positive termin-al of said energy source to the positive terminal of said contact actuating means and the negative terminal of such actuating means to a firs-t side of said first energy storing device,

(f) a resistor,

(g) second circuit means connecting the positive terminal of said energy source to one side of said resistor and the other side of said resistor to a first side of said second energy storing device,

(h) third circuit means responsive to an actuation vof saidfirst circuit controller for connecting the second vsides of said first and second energy storing devices to the negative terminal of said energy source to charge said devices, and

(i) fourth circuit means thereafter responsive to an actuation of said second circuit controller for instantaneously discharging said second energy storing device.

3. In combination:

(a) first and second normally open circuit controllers each actuable to a circuitl closing position,

(b) first and second electrical energy storing devices,

(c) a source of direct current'energy,

(d) a relay magnetic-ally biased to a first position and actuable to a second position only when the positive and negative terminals of a source of direct current energy are connected to first and second terminals respectively of the relay,

(e) aresistor,

(f) a first electrical conductor connecting the positive terminal of said energy source to said second terminal of said relay and to one end of said resistor,

(g) a second electrical conductor connecting said rst terminal of said relay yto one side of said first energy storing device,

(It) a ythird electrical conductor connecting the other end of said resistor to one side of said second energy storing device, t

() circuit means responsive to an actuation of said first circuit controller to its closed position for connecting the other sides of both said energy storing devices to the negative source, and y (j) other circuit rnc-ans responsive to an actu-ation of said second circuit controller to its closed position 5 for connecting said other end of said resistor and said one side of said second energy storing device to said other sides of both said energy storing devices.

4. Apparatus responsive only to a predetermined sequence of contact closing actuation of first and second circuit controllers having normally open contacts, said apparatus comprising, in combination: f

(a) a relay having a winding requiringjdirect current therethrough in. a predetermined directionfor pickup of the contacts ofthe relay, t

(b) a capacitor connected in aV series circuit with the Winding of said relay,

(c) alsource of direct current,

(d) circuit means responsive to an actuation of said rst circuit controller prior to an actuation of said second circuit controller for supplying direct current from said source to said series circuit ina direction opposite to `said predetermined direction, and

(e) circuit means thereafter responsive to the actuation of said second circuit controller for discharging said capacitor through the Winding of said relay in said predetermined direction.

5. Apparatus responsive only to a predetermined sequence of operation of rst and second circuit controllers, said apparatus comprising, in combination:

(a) a relay having a Winding requiring current therethrough in a predetermined direction for pickup of the relay,

(b) a capacitor,

(c) a source of direct current,

(d) means responsive to an operation of said first circuit controller prlor to an operation of said second circuit controller for charging said capacitor with direct current iiowing from said source through the Winding of said relay in a direction opposite to said at predetermined direction, and

(e) means thereafter responsive to an operation of said second circuit controller for discharging said capacitor through the winding of said relay in said predetermined direction. y

6. Apparatus responsive only to a predetermined sequence of actuation of first and second circuit controllers, said apparatus comprising, in combination:

(a) a relay having a winding requiring current Vof a first polarity therethrough for actuation of the relay,

(b) a capacitor connected in series with said winding,

(c) means responsive toan actuation of said first circuit controller prior to an actuation of said second circuit controller for supplying current of a 4second polarity to said winding and said capacitor, and

(d) means thereafter responsive to an actuation of said second circuit controller for discharging said capacitor through said winding.

7. Apparatus responsive only to a predetermined sequence ofk actuation of first and second circuit controllers, said apparatus comprising, in combination:

(a) a capacitor,

(b) means responsive to an actuation of said first circuit controller prior to an actuation of said second circuit controller for charging said capacitor,

(c) means' thereafter responsive to an actuation of said second circuit controller for discharging said capacitor, and

(d) a relay energized in response to said discharging of said capacitor. Y

8. Apparatus responsive only to a predetermined sequence of actuation of first and second circuit controllers, said apparatus comprising, in combination:

(a) an energy storage device,

(b) means responsive to an actuation of said first cirterminal of said energy cuit controller prior to an actuation of said second controller for charging said energy storage device,

(c) means thereafter responsive to an actuation of said second controller for discharging the energy stored in said storage device, and

(d) a relay connected to be energized in response to the discharge of said energy.

9. Apparatus for energizing a relay only in response to a predetermined sequence of actuation of rst and second circuit controllers, said apparatus comprising, in combination:

(a) a source of direct current,

(b) first and second energy storing devices,

(c) means responsive to an actuation of said first circuit controller prior to an actuation of said second circuit controller for charging said energy storing devices from said source of current,

(d) means thereafter responsive to an actuation`- of said second circuit controller for immediately discharging said second energy storing device, and

(e) means thereafter responsive to the return of said circuit controllers to their unactuated condition for discharging said tirst energy storing device into said second storing device and for energizing said relay in response to the discharge of such iirst device.

10. Apparatus for energizing a relay only in response to a predetermined sequence of actuation of first and second circuit controllers, said apparatus comprising, in combination:

(a) a first source of direct current energy,

(b) an energy storing device,

(c) means responsive to an actuation of said first circuit controller for charging said energy storing device from said source of energy,

(d) means thereafter responsive to an actuation of said second circuit controller for discharging said energy storing device,

(e) a normally nonconducting electronic switching device connected to be switched to a conducting condition by the discharge of energy from said energy storing device,

(f) a second source of direct current energy, and

(g) circuit means for energizing said relay from said second source of energy in response to the switching of said electronic device to the conducting condition.

ll. Apparatus responsive only to a predetermined sequence of actuation of first and second circuit controllers, said apparatus comprising, in combination:

(a) an energy storing device,

(b) means responsive to an actuation of said first circuit controller for storing energy in said device,

(c) means thereafter responsive to an actuation of said second circuit controller for discharging the energy stored in said device,

(d) a normally nonconducting electronic switching de- 55 vice connected to be switched to a conducting condition by the discharge of energy from said energy storing device, and

(e) an electrically actuated device connected to be energized in response to the switching of said electronic device to a conducting condition.

l2. In combination:

(a) first and second sets of normally open contacts each set actuable to a circuit closing condition,

(b) first and second capacitors,

(c) a source of direct current energy,

(d) means including said source of energy for charging said capacitors in response to an actuation of said lirst set of contacts prior to an actuation of said second set of contacts,

(e) means thereafter responsive to an actuation of said second set of contacts for immediately discharging said second capacitor,

(f) means including said second capacitor for discharging said first capacitor in response to the return of said irst and second sets of contacts in that order to their normal condition, and

(g) a relay connected to be energized in response to said discharging of said rst capacitor.

`13. In combination:

(a) first and second circuit controllers each having a set of contacts in a normally open condition and actuable to a circuit closing condition,

(b) first and second capacitors,

(c) a first source of direct current energy,

(d) means including said source of energy for charging said capacitors in response to an actuation of said tirst circuit controller prior to an actuation of said second circuit controller,

(e) means thereafter responsive to an actuation of said second circuit controller for immediately discharging said second capacitor;

(f) means including said second capacitor, and further thereafter responsive rto the return of said tirst and second circuit controllers in that order to their normally open contact condition, for discharging said first capacitor;

(g) a normally nonconducting electronic switching device connected to be switched to a conducting condition in response to said discharging of said capacitor,

(l1) a second source of direct current energy,

(i) a relay, and

(j) circuit means including said second source of energy for energizing said relay in response to the switching of said electronic device to the conducting condition.

14. Apparatus in accordance with claim 13 and in which said electronic switching device comprises a PNP type transistor.

References Cited by the Examiner UNITED STATES PATENTS 2,465,794 3/49 Fereday 317-135 X 2,773,221 12/56 Shaw 317-135 2,788,473 4/57 Breckman 317-151 SAMUEL BERNSTEIN, Primary Examiner. 

1. MEANS FOR DETECTING A PREDETERMINED SEQUENCE OF ACTUATION TO CIRCUIT CLOSING POSITIONS OF FIRST AND SECOND NORMALLY OPEN CIRCUIT CONTROLLERS, SAID MEANS, COMPRISING, IN COMBINATION: (A) A CAPACITOR, (B) A SOURCE OF DIRECT CURRENT ENERGY, (C) ELECTRICAL CONTACT CONTROLLING MEANS ACTUATED ONLY WHEN DIRECT CURRENT ENERGY IS SUPPLIED THERETO IN A PREDETERMINED DIRECTION, (D) FIRST CIRCUIT MEANS RESPONSIVE TO AN ACTUATION OF SAID FIRST CIRCUIT CONTROLLER PRIOR TO AN ACTUATION OF SAID SECOND CIRCUIT CONTROLLER FOR SUPPLYING DIRECT CURRENT ENERGY FROM SAID SOURCE TO SAID CONTACT CONTROLLING MEANS INA DIRECTION OPPOSITE TO SAID PREDETERMINED DIRECTION AND AT THE SAME TIME TO SAID CAPACITOR FOR CHARGING THEREOF, AND (E) SECOND CIRCUIT MEANS RESPONSIVE THEREAFTER TO AN ACTUATION OF SAID SECOND CIRCUIT CONTROLLER FOR DISCHARGING SAID CAPACITOR THROUGH SAID CONTACT CONTROLLING MEANS IN SAID PREDETERMINED DIRECTION. 